In recent years, a display device including a liquid crystal panel as a flat display portion, as typified by a liquid crystal display device, is becoming the mainstream of, e.g., a household television receiver. The liquid crystal panel has many features such as thinness and light weight compared to a conventional Broun tube. Such a liquid crystal display device includes an illuminating device (backlight) and a liquid crystal panel. The illuminating device emits light and the liquid crystal panel displays a desired image by serving as a shutter with respect to light from a light source provided in the illuminating device. The television receiver displays information such as characters and images contained in video signals of a television broadcast on the display surface of the liquid crystal panel.
The above illuminating device is broadly divided into a direct type and an edge-light type depending on the arrangement of the light source with respect to the liquid crystal panel. A liquid crystal display device including a liquid crystal panel of 20 inches or more generally uses the direct type illuminating device that can achieve high brightness and large size more easily than the edge-light type illuminating device. In the direct type illuminating device, a plurality of light sources are located on the back (non-display surface) side of the liquid crystal panel. Since the light sources are located directly on the back side of the liquid crystal panel, many light sources can be used, and the brightness can be easily increased. Therefore, the direct type illuminating device is suitable for high brightness and large size. Moreover, the direct type illuminating device has a hollow structure and is light-weight even if the size is increased. In this regard, the direct type illuminating device is suitable for high brightness and large size.
In the above conventional illuminating device, as described in, e.g., Patent Document 1, a plurality of hot-cathode fluorescent tubes are provided as light sources, each of the hot-cathode fluorescent tubes has sockets at both ends, and the individual hot-cathode fluorescent tubes are connected to a lighting drive circuit via cables connected to the sockets. In the conventional illuminating device, it is proposed to drive the hot-cathode fluorescent tubes by high-frequency lighting of the lighting drive circuit.